1. Field of the Invention
This invention relates to a process for producing methacrylic acid by oxidative dehydrogenation of isobutyric acid.
2. Description of the Prior Art
It is known that catalysts which contain a molybdophosphoric acid in which molybdenum may be partly replaced by vanadium and/or tungsten, and/or a reduced form thereof as a main component are used in the manufacture of methacrylic acid by oxidative dehydrogenation of isobutyric acid (Japanese Patent Laid-Open Application No. 78120/1973). Although the catalysts are highly active and suitable for use as catalyst for the production of methacrylic acid, they are not completely satisfactory with respect to catalyst life.